Dr Matilda Dunn, a policy analyst at Green Alliance, has warned that the expansion of biomethane production in the UK risks substituting one set of environmental problems for another. While biomethane is often touted as a solution to reduce reliance on North Sea gas and imports, Dunn highlights serious environmental and health risks associated with its growth.
Although biogas produced from waste can cut emissions, the latest figures show a growing share of feedstock for anaerobic digestion comes from purpose-grown energy crops. This increases pressure on land, competes with food production, and risks wider environmental harm.
Methane leakage from anaerobic digestion sites is a significant concern, with studies suggesting up to 13% of methane can escape. Given methane's powerful warming effect, this is no small issue. Current requirements for detecting and repairing leaks are not mandated or well enforced.
Ammonia emissions from the sector are also rising, produced when nitrogen-rich feedstock breaks down in digesters. Ammonia contributes to the formation of harmful particulate matter (PM2.5) and damages sensitive habitats, worsening air quality and ecosystem health.
Dunn notes that biomethane is unlikely to meet more than 18% of current gas demand, according to some estimates. Without stronger safeguards, its expansion risks creating new environmental problems rather than solving existing ones.
